From 79b569f0ec53a14c4d71e79d93a8676d9a0fda6d Mon Sep 17 00:00:00 2001 From: Daniel Lezcano Date: Wed, 30 Mar 2011 02:42:17 -0700 Subject: [PATCH] netdev: fix mtu check when TSO is enabled In case the device where is coming from the packet has TSO enabled, we should not check the mtu size value as this one could be bigger than the expected value. This is the case for the macvlan driver when the lower device has TSO enabled. The macvlan inherit this feature and forward the packets without fragmenting them. Then the packets go through dev_forward_skb and are dropped. This patch fix this by checking TSO is not enabled when we want to check the mtu size. Signed-off-by: Daniel Lezcano Acked-by: "Eric W. Biederman" Signed-off-by: David S. Miller --- net/core/dev.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 563ddc28139d..3da9fb06d47a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1454,6 +1454,27 @@ static inline void net_timestamp_check(struct sk_buff *skb) __net_timestamp(skb); } +static inline bool is_skb_forwardable(struct net_device *dev, + struct sk_buff *skb) +{ + unsigned int len; + + if (!(dev->flags & IFF_UP)) + return false; + + len = dev->mtu + dev->hard_header_len + VLAN_HLEN; + if (skb->len <= len) + return true; + + /* if TSO is enabled, we don't care about the length as the packet + * could be forwarded without being segmented before + */ + if (skb_is_gso(skb)) + return true; + + return false; +} + /** * dev_forward_skb - loopback an skb to another netif * @@ -1477,8 +1498,7 @@ int dev_forward_skb(struct net_device *dev, struct sk_buff *skb) skb_orphan(skb); nf_reset(skb); - if (unlikely(!(dev->flags & IFF_UP) || - (skb->len > (dev->mtu + dev->hard_header_len + VLAN_HLEN)))) { + if (unlikely(!is_skb_forwardable(dev, skb))) { atomic_long_inc(&dev->rx_dropped); kfree_skb(skb); return NET_RX_DROP; -- GitLab